EXPLANATION OF THE PLATES. 343 



water to the condenser is regulated by a cock, moved by the handle c on the 

 spindle d. 



The governor g (see art. 550.) is kept in motion by bands from the crank shaft, 

 and opens or closes the throttle valve in the steam pipe C by means of a lever // h. 

 See Plate vnr. Fig. 1. 



The proportion of the parts for a double engine of this kind may be ascertained 

 by art. 414 423. It ought to be made to work expansively, but in this case it 

 has not been done : the saving resulting from causing the engine to work ex- 

 pansively, will be in the ratio of about 10 to 7 to do the same work, (art. 422.) 

 See Table in. art. 664. 



PLATE XV. 



As an example of a portable condensing engine for impelling machinery, I have 

 taken that of Mr. Maudslay, where the beam is omitted, and the crank connected 

 directly with the piston rod. Fig. 1. is a front elevation of an engine ; Fig. 2. 

 a longitudinal section ; and Fig. 3. an end view. The cylinder B is supported by 

 a cast iron frame A, and C is the piston, with the rod D, connected to a cross head 

 at E, and guided by the wheel F, which keeps the piston rod in a vertical direction, 

 by moving in the frame G ; the side rods H H connect the cross head E with the 

 double crank I I, which turns in the plummer blocks or bearings J J, one on 

 each side of the frame, and to which the fly wheel shaft K, carrying a fly wheel M, 

 is connected by a coupling box, or clutch L, at the end next the engine. 



Two eccentric wheels N N, on the crank shaft K, give motion to the levers O 

 and T, by means of the connecting rods P P. The lever O, supported by the 

 bearing Q, works the cold water pump S, by the rod R ; while the beam T, 

 working on the centre V, works the air pump X by the slings v, and the hot 

 water pump Y ; which by the feed pipe Z supplies the boiler with hot water. On 

 the cross rail (a) the guide is fixed to confine the air pump rod to a vertical motion ; 

 the condenser b surrounds the air pump, and is again surrounded by one of the 

 cold water cisterns c ; the two cisterns are connected by a pipe d : the steam from 

 the cylinder passes to the condenser through the eduction pipe e, and the cold 

 water for injection is admitted to the condenser by the cock/. The air and con- 

 densed steam ascends through the foot valve g in the bottom into the air pump. 



